IBM Selectric

As Cold War tensions increased throughout the 1970s, the Soviets pulled out all the stops when it came to digging up information from US diplomats. This NSA memo from 2012 explains how several IBM Selectric typewriters used in the Moscow and Leningrad offices were successfully bugged with electromechanical devices that could possibly have been the world’s first keyloggers.

The Selectric prints with a ball that is spun and tilted to select the desired character. Two mechanical arms control the ball’s spin and tilt, and the keylogger read out the position of those arms. Thus, each character on the Selectric’s type element ball has its own signature. The sensing part of the keylogging mechanism was buried in part of the typewriter chassis, a metal bar that spans the width of the machine, and were so well hidden that they could only have been detected by complete dissassembly or x-ray.

In the days when computers took up an entire room, a CRT monitor was a luxury. Most of the time, input and output was handled with a teletype – a typewriter connected directly to the computer. [Josh] wanted his own typewriter terminal, so he took apart an IBM Selectric II and got to work.

Instead of an electronic keyboard, the IBM Selectric II uses and electromechanical keyboard to tilt and rotate the Selectric’s typeball. In normal operation, a series of shafts underneath the keyboard are engaged. [Josh] added parts of an erector set to those levers and tied each one to one of 16 solenoids.

With a set of solenoids able to print any key with the help of an Arduino, [Josh] had a fully automated typewriter from the early 1970s. [Josh has been printing out a lot of ASCII art lately in preparation for the Kansas City Maker Faire later this month. You can check out the build videos after the break.